This invention relates to diplatinum complexes and in particular to diplatinum complexes useful as anti-tumor agents.
The use of transition metal complexes as anti-tumor agents is well documented. While complexes of copper, palladium and iridium have been shown to be effective anti-tumor agents, platinum complexes have recently been receiving most attention.
For example, U.S. Pat. No. 4,177,263 to Rosenberg et al. discloses the effectiveness of cis-dichlorodiammine-platinum (II) (Pt(II)Cl.sub.2 (NH.sub.3).sub.2) in the treatment of malignant tumors. U.S. Pat. No. 4,140,707 to Cleare et al. relates to malonato platinum coordination compounds and methods of treating malignant tumors comprising the parenteral administration to an affected animal of a solution of the compound. Further, U.S. Pat. No. 4,200,583 discloses cis-platinum (II) complexes wherein platinum (II) coordinates, 1,2-diamino-cyclohexane (cis-, trans-l or trans-d) are disclosed to exhibit anti-tumor activity.
While platinum complexes, particularly cis-dischlorodiammine-platinum (II) (cis-DDP), have been found to be relatively effective for the treatment of a variety of tumors, one disadvantage associated with their use is the high degree of toxicity. Moreover, tumor cells, previously susceptible to certain platinum complexes, such as cis-dichlorodiammine-platinum (cis-DDP), have been discovered which are highly resistant to the compound.
Accordingly, new platinum complexes which eliminate or minimize the disadvantages of the prior art materials are desirable.